Smokeless powder



Patented Apr. 13, 1937 SMOKELESS rownna Ellsworth S. Goodyear, Kenvll, N. J., assignor to Hercules Powder Company, Wilmington, Del., a corporation of Delaware No Drawing.

11 Claims.

This invention relates toanimprovement in smokeless powder and more particularly relates to an improved coated powder.

Heretofore it has been known to coat smoke- 5 less powders with various coating agents in order to secure, desired ballistic properties, ballistic stability and chemical stability, andit has been found-that of the various coating agents used heretofore certain alkyl ester solvent plasticizers 10 for nitrocellulose, and especially diethyl phthalate, have been found to be most satisfactory. However, despite the satisfactory control on ballistic properties, ballistic and chemical stability obtained with use of diethyl phthalate as a 15 coating agent, it has been found that powders coated therewith show the highly undesirable property of becoming faster when stored at elevated temperatures and that it is very difficult to produce duplicate lots of powder when using di- 2 ethyl phthalate as the coating agent.

Now in accordance with this invention it has been found that alkyl phthalyl alkyl glycollates lend themselves to the coating of smokeless powder for control of ballistics, of ballistic stability 25 and of chemical stability as effectively as does dlethyl phthalate and at the same time enables the production of powders showing a greatly increased resistance to ballistic change under storage at elevated temperatures, and enable the du- 30 plication of lots of powder with the greatest ease. In proceeding in accordance with this invention any type of smokeless or nitrocellulose powder,

,such for example, as single base powders and double base powders may be used and any suit-- as able alkyl phthalyl alkyl glycollate, such as, for

example, .butyl' phthalyl butyl glycollate, ethyl phthalyl ethyl glycollate, methyl phthalyl ethyl glycollate, or the like, or mixtures thereof, may be used.

40 The production of smokeless powders in accordance with this invention may be accomplished in any suitable or well known manner, as, for example, by tumbling the powder of any desired composition in a sweetie barrel with the 45 glycollate at a temperature at which it will be relatively liquid, or with a solution of the glycollate in any suitable solvent therefor which is relatively a non-solvent for the nitrocellulose of the smokeless powder, such as benzol or toluoi,

50 or with a solvent for the nitrocellulose of the powder such as, for example, ethyl alcohol or methyl alcohol, though when ethyl or methyl a1- cohol are used they will preferably be' diluted with water in order to, decrease their solvent power.

55 The powder and coating agent, or solution there- Application December 4, 1934, Serial No. 155,876

of, may be tumbled under any suitable or desired temperature condition, but in the caseof a solution will desirably be tumbled for a period at a relatively low temperature, to permit the coating agent, which will, due to the alkyl phthalyl 5 radicals, have a solvent action on the powder, to penetrate and then tumbled at increasing temperature. Minimum and maximum temperatures used will vary widely with particular powders, vamount of coating agent, solvent used and properties desired for the finished powder. Generally speaking, the use of temperature within about the range C.-90 C. will give satisfactory results. The alkyl phthalyl alkyl glycollates may be used in widely varying amounts or proportions 15 relative to the amount of powder coated, depending upon the particular powder treated and the properties desired for the particular powder. Generally speaking, for purposes of illustration,

alkyl phthalyl alkyl glycollate in amount within about-the range 0.5%-5% by weight of the powder will be found to give satisfactory results.

In the application of v the alkyl phthalyl alkyl glycollates in solution, solutions of any desired concentration may be used. However, solutions having a concentration of coating agent within about the range 5% -40% by weight of the solvent will give satisfactory results.

As more specifically illustrative of the practical adaptation of this invention, for example, a satisfactory rifle powder may be produced by tumbling 2 pounds of double base powder containing 20% of nitroglycerine in a sweetie barrel with a solution of 36.2 grams of butyl phthalyl butyl glycollate (4% by weight of the powder) in solution in 80 cc. of ethyl alcohol containing 12 cc. of added water. The tumbling will be carried on for 15 minutes at 15 C. and then with gradual increase in temperature up to about 90 C. until the powder has been tumbled for a total of one 40 our.

As further illustrative using the procedure and conditions given in'the above example, a satisfactory powder will be produced by tumbling for one hour two pounds of flake shotgun powder with 2%, or 18.1 grams, of methyl phthalyl ethyl glycollate dissolved in 80 cc. of ethyl alcohol containing 1'7 cc. of added water.

The procedure, proportions, conditions, etc. given in the above examples may be widely varied, depending upon the particular powder coated and the properties desired for the finished powder.

It will be understood that this invention contemplates broadly smokeless powder of any type coated with an alkyl phthalyl alkyl glycollate by the use of any suitable procedure and that the examples and details of procedure given herein are for illustrative purposes only and shall not be deemed as limiting upon the scope of this invention.

What I claim and desire'to protect by Letters Patent is:

1. A smokeless powder coated with an alkyl 10 Dhthalyl alhl glycollate.

2. A double base smokeless powder coated with an alkyl phthalyl alkyl glycollate.

3. A smokeless powder coated with butyl phthalylbutyi glycollate. I

4. A ,smokeless powder coated with ethyl phthalyl ethyl glycollate.

5. A smokeless powder coated with methyl phthalyl ethyl glycollate.

6. A double base smokeless powder coated with' butyl phthalyl butyl glycollate.

'7. A double base smokeless powder coated with ethyl phthalyl ethyl glycollate. v

8. A double base smokeless powder coated with methyl phthalyl ethyl glycollate.

9. A smokeless powder coated with 01' alkyl phthalyl alkyl glycollates.

10. A double base smokeless powder coated with a mixture of alkyl phthalyl alkyl glycollates.

11. A smokeless powder coated with an alkyl phthalyl alhl glycollate in amount from about a mixture 0.5% to about 5% by weight of the powder.

ELLSWORTH S. GOODYEAR. 

